import java.sql.*;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {

        // 查询
        //m1();

        // 条件查询
        //m2();

        // 增加
        //m3();

        // 删除
        //m4();

        // 修改
    }

    private static void m4() {
        try {

            //1.加载驱动
            Class.forName("com.mysql.cj.jdbc.Driver");

            //2.创建连接
            String URL = "jdbc:mysql://127.0.0.1:3306/student?characterEncoding=utf-8";
            Connection connection = DriverManager.getConnection(URL, "root", "Win032917.lx");
            /*
            if(connection!= null){
                System.out.println("连接成功");
            }
             */
            //3.执行SQL语句
            String sql = "delete from student where id = ?";
            //4.预编译SQL语句
            PreparedStatement preparedStatement = connection.prepareStatement(sql);
            //5.有参数设参数
            preparedStatement.setObject(1, "6");
            //6.执行SQL语句
            int result = preparedStatement.executeUpdate();

            //7.结果判断
            if (result > 0) {
                System.out.println("删除成功");
            }
            //8.关闭连接
            preparedStatement.close();
            connection.close();
        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }

    }
    private static void m3() {
        // 1、加载驱动
        try {

            // Scanner
            Scanner sc = new Scanner(System.in);
            System.out.print("请输入要新增的id：");
            int id = sc.nextInt();
            System.out.print("请输入要新增的姓名：");
            String name = sc.next();
            System.out.print("请输入要新增的学号：");
            String number = sc.next();

            Class.forName("com.mysql.cj.jdbc.Driver");

            // 2、获取连接 (url username password)
            String url = "jdbc:mysql://127.0.0.1:3306/student?characterEncoding=utf-8";
            Connection connection = DriverManager.getConnection(url, "root", "Win032917.lx");
//            if (connection != null) {
//                System.out.println("连接成功");
//            }
            // 3、写sql
            String sql = "insert into student(id,name,number) values (?,?,?) ";

            // 4、预编译sql
            PreparedStatement preparedStatement = connection.prepareStatement(sql);

            // 5、有参数设置参数
            preparedStatement.setObject(1,id);
            preparedStatement.setObject(2,name);
            preparedStatement.setObject(3,number);

            // 6、执行sql  executeUpdate
            int result = preparedStatement.executeUpdate();

            // 7、结果判断
            if (result > 0) {
                System.out.println("新增成功");
            }

            // 8、关闭资源
            preparedStatement.close();
            connection.close();


        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }

    private static void m2() {
        // 1、加载驱动
        try {

            // Scanner
            Scanner sc = new Scanner(System.in);
            System.out.print("请输入你要查询的姓名：");
            String word = sc.next();

            Class.forName("com.mysql.cj.jdbc.Driver");

            // 2、获取连接 (url username password)
            String url = "jdbc:mysql://127.0.0.1:3306/student?characterEncoding=utf-8";
            Connection connection = DriverManager.getConnection(url, "root", "Win032917.lx");
//            if (connection != null) {
//                System.out.println("连接成功");
//            }
            // 3、写sql
            String sql = "select * from student where name like ? ";

            // 4、预编译sql
            PreparedStatement preparedStatement = connection.prepareStatement(sql);

            // 5、有参数设置参数
            preparedStatement.setObject(1,"%"+word+"%");

            // 6、执行sql
            ResultSet resultSet = preparedStatement.executeQuery();

            // 7、遍历结果集
            while(resultSet.next()) {
                int id = resultSet.getInt(1);
                String name = resultSet.getString(2);
                String number = resultSet.getString(3);
                System.out.println(id + " " + name + " " + number);
            }

            // 8、关闭资源
            resultSet.close();
            preparedStatement.close();
            connection.close();


        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }

    private static void m1() {
        // 1、加载驱动
        try {

            //1.加载驱动
            Class.forName("com.mysql.cj.jdbc.Driver");

            //2.创建连接
            String URL = "jdbc:mysql://127.0.0.1:3306/student?characterEncoding=utf-8";
            Connection connection = DriverManager.getConnection(URL, "root", "Win032917.lx");
            /*
            if(connection!= null){
                System.out.println("连接成功");
            }
             */
            //3.执行SQL语句
            String sql = "SELECT * FROM student";
            //4.预编译SQL语句
            PreparedStatement preparedStatement = connection.prepareStatement(sql);
            //5.有参数设参数
            //6.执行SQL语句
            ResultSet resultSet = preparedStatement.executeQuery();

            //7.遍历结果集
            while(resultSet.next()) {
                int id = resultSet.getInt(1);
                String name = resultSet.getString(2);
                String number = resultSet.getString(3);
                System.out.println(id + " " + name + " " + number);
            }
            //8.关闭连接
            resultSet.close();
            preparedStatement.close();
            connection.close();
        } catch (ClassNotFoundException e){
            throw new RuntimeException(e);
        }catch (SQLException e){
            throw new RuntimeException(e);
        }
    }
}